The diastereoselective synthesis of syn-α-alkyl α-hydroxy β-amino acids 4a-h was easily accomplished by reaction of the sodium dianion of the corresponding anti α-alkyl β- benzoylamino acid methyl esters with iodine. The intermediate α-iodo derivatives spontaneously afforded cis-oxazolines which, upon hydrolysis, provided the desired products, with diastereoselectivities up to 99: 1.
